Sequential Ring-Closing Metathesis and Silicon-Assisted Cross-Coupling Reactions: Stereocontrolled Synthesis of Highly Substituted Unsaturated Alcohols
作者:Scott E. Denmark、Shyh-Ming Yang
DOI:10.1021/ol015950j
日期:2001.5.1
A sequential ring-closingmetathesis/silicon-assisted cross-coupling sequence has been developed. Alkenyldimethylsilyl ethers of omega-unsaturated alcohols undergo facile ring closure with Schrock's catalyst to afford five-, six-, and seven-membered cycloalkenylsiloxanes bearing substituents on both alkenyl carbons. These siloxanes were highly effective coupling partners with various aryl and alkenyl
Cross-coupling reaction of organosilicon nucleophiles
申请人:——
公开号:US20020183516A1
公开(公告)日:2002-12-05
Improved methods for generating a —C—C— bond by cross-coupling of a transferable group with an acceptor group. The transferable group is a substituent of an organosilicon nucleophile and the acceptor group is provided as an organic electrophile. The reaction is catalyzed by a Group 10 transition metal complex (e.g., Ni, Pt or Pd), particularly by a palladium complex. Certain methods of this invention use improved organosilicon nucleophiles which are readily prepared, can give high product yields and exhibit high stereo selectivity. Methods of this invention employ activating ions such as halides, hydroxide, hydride and silyloxides. In specific embodiments, organosilicon nucleophilic reagents of this invention include siloxanes, particularly cyclic siloxanes. The combination of the cross-coupling reactions of this invention with ring-closing metathesis, hydrosilylation and intramolecular hydrosilylation reactions provide useful synthetic strategies that have wide application.
Sequential ring-closing metathesis/Pd-catalyzed, Si-assisted cross-coupling reactions: general synthesis of highly substituted unsaturated alcohols and medium-sized rings containing a 1,3-cis–cis diene unit
作者:Scott E. Denmark、Shyh-Ming Yang
DOI:10.1016/j.tet.2004.06.149
日期:2004.10
construction of medium-sized rings with an internal 1,3-cis–cis diene unit. The formation of 9-, 10-, 11-, and 12-membered carbocyclic dienes is achieved in good yield. Extension to the synthesis of 9-membered ring unsaturatedethers has also been accomplished. Noteworthy features of this process include: (1) highly stereospecific intramolecular coupling, (2) flexible positioning of the revealed hydroxy group
Rendering Schrock-type Molybdenum Alkylidene Complexes Air Stable: User-Friendly Precatalysts for Alkene Metathesis
作者:Johannes Heppekausen、Alois Fürstner
DOI:10.1002/anie.201102012
日期:2011.8.16
A matter of convenience: Schrock molybdenumalkylidenes are amongst the most powerful olefin metathesis catalysts known to date, but their sensitivity to air and moisture mandates their handling in a glove‐box or by Schlenk techniques. This inconvenience is circumvented by using the corresponding phenanthroline‐ or bipyridine adducts, which are bench‐stable and hence very user‐friendly. The active